Quincy is located in Adams county Illinois with a geographic area of 15.8 square miles. The total population in Quincy is 40,111 with 48.0% male and 52.0% female. Children under age 5 represent 6.5% of the population, under age 18 equal 21.4% of the population and over age 65 is 20.7% of the population. The median household income is $46,935, per capita income is $29,105. There are a total of 17,226 housing units with 63.5% owner occupied. Education includes 28.5% of residents that are high school graduates and 26.0% with a bachelor's degree or higher. The average temperature in Quincy in the summer is 74 degrees, and in the winter 27 degrees.
